A turbofan engine typically includes a fan section, a compressor section, a combustor section and a turbine section. Air entering the compressor section is typically compressed and delivered into the combustor section where it is mixed with fuel and ignited to generate a high-pressure, high-temperature gas flow. The high-pressure, high-temperature gas flow expands through the turbine section to drive the compressor and the fan section.
A direct-drive turbofan engine typically includes a fan section directly driven by a low pressure turbine producing the power needed to drive the fan section, such that the low pressure turbine and the fan section rotate at a common rotational speed in a common direction. A power transmission device such as a gear assembly or other mechanism may be utilized to drive the fan section such that the fan section may rotate at a speed different than the turbine section so as to increase the overall efficiency of the engine. In a gear-drive turbofan engine architecture, a shaft driven by one of the turbine sections may provide an input to the speed reduction device that drives the fan section at a reduced speed such that both the turbine section and the fan section can rotate at closer to their respective optimal rotational speeds.